/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.googlecode.bluetools.dom4j;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import com.googlecode.bluetools.dom4j.tree.QNameCache;
import com.googlecode.bluetools.dom4j.util.SingletonStrategy;

/**
 * <p>
 * <code>QName</code> represents a qualified name value of an XML element or attribute. It consists of a local name and
 * a {@link Namespace}instance. This object is immutable.
 * </p>
 * 
 * @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
 */
public class QName implements Serializable {
	/** The Singleton instance */
	private static SingletonStrategy singleton = null;

	static {
		try {
			String defaultSingletonClass = "com.bluebamboo.dom4j.util.SimpleSingleton";
			Class clazz = null;
			try {
				String singletonClass = defaultSingletonClass;
				singletonClass = System.getProperty("com.bluebamboo.dom4j.QName.singleton.strategy", singletonClass);
				clazz = Class.forName(singletonClass);
			}
			catch (Exception exc1) {
				try {
					String singletonClass = defaultSingletonClass;
					clazz = Class.forName(singletonClass);
				}
				catch (Exception exc2) {
				}
			}
			singleton = (SingletonStrategy) clazz.newInstance();
			singleton.setSingletonClassName(QNameCache.class.getName());
		}
		catch (Exception exc3) {
		}
	}

	/** The local name of the element or attribute */
	private String name;

	/** The qualified name of the element or attribute */
	private String qualifiedName;

	/** The Namespace of this element or attribute */
	private transient Namespace namespace;

	/** A cached version of the hashcode for efficiency */
	private int hashCode;

	/** The document factory used for this QName if specified or null */
	private DocumentFactory documentFactory;

	public QName(String name) {
		this(name, Namespace.NO_NAMESPACE);
	}

	public QName(String name, Namespace namespace) {
		this.name = (name == null) ? "" : name;
		this.namespace = (namespace == null) ? Namespace.NO_NAMESPACE : namespace;
	}

	public QName(String name, Namespace namespace, String qualifiedName) {
		this.name = (name == null) ? "" : name;
		this.qualifiedName = qualifiedName;
		this.namespace = (namespace == null) ? Namespace.NO_NAMESPACE : namespace;
	}

	public static QName get(String name) {
		return getCache().get(name);
	}

	public static QName get(String name, Namespace namespace) {
		return getCache().get(name, namespace);
	}

	public static QName get(String name, String prefix, String uri) {
		if (((prefix == null) || (prefix.length() == 0)) && (uri == null)) {
			return QName.get(name);
		}
		else if ((prefix == null) || (prefix.length() == 0)) {
			return getCache().get(name, Namespace.get(uri));
		}
		else if (uri == null) {
			return QName.get(name);
		}
		else {
			return getCache().get(name, Namespace.get(prefix, uri));
		}
	}

	public static QName get(String qualifiedName, String uri) {
		if (uri == null) {
			return getCache().get(qualifiedName);
		}
		else {
			return getCache().get(qualifiedName, uri);
		}
	}

	public static QName get(String localName, Namespace namespace, String qualifiedName) {
		return getCache().get(localName, namespace, qualifiedName);
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the local name
	 */
	public String getName() {
		return name;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the qualified name in the format <code>prefix:localName</code>
	 */
	public String getQualifiedName() {
		if (qualifiedName == null) {
			String prefix = getNamespacePrefix();

			if ((prefix != null) && (prefix.length() > 0)) {
				qualifiedName = prefix + ":" + name;
			}
			else {
				qualifiedName = name;
			}
		}

		return qualifiedName;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the namespace of this QName
	 */
	public Namespace getNamespace() {
		return namespace;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the namespace URI of this QName
	 */
	public String getNamespacePrefix() {
		if (namespace == null) {
			return "";
		}

		return namespace.getPrefix();
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the namespace URI of this QName
	 */
	public String getNamespaceURI() {
		if (namespace == null) {
			return "";
		}

		return namespace.getURI();
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the hash code based on the qualified name and the URI of the namespace.
	 */
	public int hashCode() {
		if (hashCode == 0) {
			hashCode = getName().hashCode() ^ getNamespaceURI().hashCode();

			if (hashCode == 0) {
				hashCode = 0xbabe;
			}
		}

		return hashCode;
	}

	public boolean equals(Object object) {
		if (this == object) {
			return true;
		}
		else if (object instanceof QName) {
			QName that = (QName) object;

			// we cache hash codes so this should be quick
			if (hashCode() == that.hashCode()) {
				return getName().equals(that.getName()) && getNamespaceURI().equals(that.getNamespaceURI());
			}
		}

		return false;
	}

	public String toString() {
		return super.toString() + " [name: " + getName() + " namespace: \"" + getNamespace() + "\"]";
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the factory that should be used for Elements of this QName
	 */
	public DocumentFactory getDocumentFactory() {
		return documentFactory;
	}

	public void setDocumentFactory(DocumentFactory documentFactory) {
		this.documentFactory = documentFactory;
	}

	private void writeObject(ObjectOutputStream out) throws IOException {
		// We use writeObject() and not writeUTF() to minimize space
		// This allows for writing pointers to already written strings
		out.writeObject(namespace.getPrefix());
		out.writeObject(namespace.getURI());

		out.defaultWriteObject();
	}

	private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
		String prefix = (String) in.readObject();
		String uri = (String) in.readObject();

		in.defaultReadObject();

		namespace = Namespace.get(prefix, uri);
	}

	private static QNameCache getCache() {
		QNameCache cache = (QNameCache) singleton.instance();
		return cache;
	}
}

/*
 * Redistribution and use of this software and associated documentation ("Software"), with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions must also contain a
 * copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived from this Software without prior written
 * permission of MetaStuff, Ltd. For written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may "DOM4J" appear in their names without prior
 * written permission of MetaStuff, Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
